The present invention relates generally to the recovery of waste gases, more specifically, the invention relates to an improved apparatus and method for the recovery of waste gases at an oil well site or at a gas well site during the production of oil or natural gas.
In the production of oil or natural gas there is a significant amount of by-product gases produced. Presently, these by-product gases are allowed to go directly into the atmosphere from a vent pipe or vent valve located on top of the oil storage tank(s), and/or on top of the salt water tank.
The production of oil or gas typically involves an oil or gas pool which requires a reservoir rock that is porous and permeable, and a trap to contain the oil or gas. The oil or gas travels from its source into and through the reservoir rock to the trap.
The trap usually is an impermeable rock which encloses above the reservoir rock. Due to buoyancy and time, the less dense oil or gas migrates to the top of the trap, displaces the saltwater, and remains in the trap. Thus, several layers form which include gas at the top, then in order, light oils, heavier oils, oil and salt water at the bottom.
Each well has its own inherent flow characteristics. The type of trap and geographical formation make up part of the natural flow characteristics of a pool of gas and oil. Common types of traps are dome, structural traps (created by relationships involving faults), and stratigraphic traps (resulting from variation in the layers, or strata).
Sedimentary rock usually forms reservoir rocks under certain conditions. Most reservoir rock consist of sandstone or limestone due to their permeable and porous characteristics. Generally, wells are drilled via a rotary bit method as is known in the art. When the drilling reaches the oil-bearing formations, the limits of the field are determined via formation samples taken during drilling and running well logs in the well casing pipe. Perforations in the casing are made at the oil and gas bearing formation zones. Production tubing is installed into the casing which is used to withdraw the oil and gas.
Initially, the rate of the flow and the pressure and volume of the well are controlled by special pipings and gate valves called a xe2x80x9cChristmas treexe2x80x9d installed above ground. The recovery of oil and gas requires the use of separation equipment to separate the natural gas from the liquid petroleum and salt water.
On some wells, initial production is usually through the mechanism of primary recovery, wherein the oil and gas field""s own pressure drives the oil or gas to the surface. Over time, the pressure in the field drops. Then, the oil must be pumped up to obtain production and difficulty resides in determining how long the pumping must be maintained for economic viability. A common drawback is that pumping the well causes removal of unwanted salt water from the well because it has a tendency to mix with the oil and gas as it enters the perforations casing as the reservoir decreases.
While some of the production gas is utilized in conventional methods, a great deal of gas is wasted and placed into the atmosphere. Accordingly, there exists a need to reduce waste production gases and to reduce hydrocarbon contamination of the atmosphere.
It is an object of the present invention to recover waste production gases.
It is another object of the invention to prevent hydrocarbon contamination of the atmosphere.
It is still another object of the invention to reduce waste of natural resources.
In the past, production gases which contain entrapped hydrocarbons have been a waste by-product of gas/oil production operations. Accordingly, the present invention provides an improved method and apparatus for the recovery of such gases during the production of oil and natural gas.
In accordance with the present invention, the waste gas from the oil/gas production operations, which was previously vented into the atmosphere, is recovered in accordance with the present invention and sold to pipeline companies. An apparatus for recovering production gas waste at an oil or gas production site is provided and includes a gas-vacuum compressor, a power source for the gas-vacuum compressor, a vacuum piping connected to a first end of the gas-vacuum compressing means and to at least one of an oil tank, a salt water tank and a separator tank for enabling removal of gas therefrom. Further, included is production gas recovery device for recovering the removed gas and discharge piping connected to a second end of said gas-vacuum compressing means for enabling transporting the removed gas via the gas-vacuum compressor means to the production recovery device.
During the production of oil or gas at the oil or gas production site, the gas waste recovery apparatus (gas compressor) of the present invention removes the waste gas inside the oil and salt water tanks, compresses the gas and then transports it to either a gas/oil/salt water separator, a gas/liquid separator, or back to the gas well head and into the well. The recovered gas is eventually pumped to a gas pipeline, or a gas pressurized tank for future pickup.